Optical ferrules which are standardized according to JIS C 5981, IEC 61754-5 and the like, are called MT (Mechanically Transferable) ferrules, and are used for connecting optical fibers. MT ferrules generally use at least two guide pins for high-accuracy positioning of each optical fiber in the ferrule. An MT ferrule body may include two guide pin holes on the end surface of the ferrule for receiving the guide pins therein, and may have a plurality of optical fiber holes for receiving the optical fibers. The respective optical fibers may be inserted into the optical fiber insertion holes from a rear end of the MT ferrule, and may be fixed in place with adhesive.
An adapter may be used for face-to face joining of two MT ferrules. MT ferrules generally have a rectangular cross-sectional shape, and likewise, the adapter may be in the shape of a rectangular cylinder for insertion of one ferrule into each end. Two MT ferrules, one with guide pins installed (male connector) and one without guide pins (female connector) are inserted into opposite ends of the adapter whereby the ferrules are aligned together with one another as the male guide pins enter the female guide pin holes. One type of connector that uses MT ferrules is an MPO (multi-fiber push-on) connector
The MT ferrules get pushed together within the adapter to optically connect the ferrules by means of a so-called PC (Physical Contact) connection, wherein the optical fibers in one ferrule contact the optical fibers in the other ferrule and get compressed together to provide an optical connection. Optical transmission performance between the optical fibers is strongly dependent on connecting conditions such as axis alignment and inclination of the optical fibers, and gaps between the opposing optical fibers.
To prevent gaps during connection, it is necessary to remove foreign materials that may be adhered to the connection end face of the MT ferrule. Any foreign materials are commonly wiped off by use of a cleaner. However, connection loss at the PC connection may be increased during wiping off, because some of the foreign materials may be gathered and deposited around base portions of the guide pins. In general, any foreign materials that may be present on the end face or components of the end face may interfere with the connection by causing the faces to be spaced apart from one another, resulting in gaps between the optical fibers.
In addition, in installations wherein the adapter is fixedly mounted in a panel, for example, the angular orientation of the ferrule as it is retrieved, aligned, and inserted may stress the optical fibers, and possibly result in breakage of a fiber or fibers if considerable care is not taken when the ferrule is inserted into the adapter.
Therefore, during the mating of MT ferrules, there remains a need for minimization of issues that may result in poor fiber mating connections, such as contamination on the end faces of the MT/MPO ferrules, and the possibility of fibers breaking when the MPO connector is inserted into an MPO adapter in a rough or incorrect manner.